


How to Cure a Shut-In

by Eroppai (FalstaffKisaragi)



Category: Gundam Build Divers
Genre: Blow Jobs, Breast Fucking, Brother/Sister Incest, Cowgirl Position, F/M, Femdom, Groping, Inspired by Fanart, Large Breasts, Loss of Virginity, Sweat
Language: English
Status: Completed
Published: 2020-06-03
Updated: 2020-06-03
Packaged: 2021-03-03 22:20:46
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,455
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24512989
Author URL: https://archiveofourown.org/users/FalstaffKisaragi/pseuds/Eroppai
Summary: Koichi hasn't come out of his apartment in a long time. Nanami still visits him regularly, but when he turns down the Build Divers' request, she takes up the case herself. Using her voluptuous body, Nanami convinces her brother to get laid and join her at the Gundam Base.
Relationships: Nanase Nanami | Nami/Nanase Koichi | KO-1
Kudos: 6





	How to Cure a Shut-In

Koichi had been living by himself for a while now. He wasn’t lacking for food or companionship, because he got both of those when his sister came to visit. Nanami had looked up to him when they were younger, even if she didn’t quite understand anything about Gundam. The way those little robots darted around the field, firing lasers and using laser blades against each other was really cool. Until the rise of VRMMOs took over, and Koichi’s specialty fell out of favor. Nanami had gotten a job at The Gundam Base in the meantime, and kept trying to get her brother to leave his room.

“I brought you some dinner,” said Nanami, knocking on the door.

“Just leave it by the front door,” said Koichi.

“We’re family. I’m not leaving you in your apartment,” said Nanami. “What are you doing in there all day?”

As his sister, she had a spare key for just such an occasion. She unlocked the door, and entered Koichi’s apartment. He was looking at a tastefully nude photobook of Mihoshi, his cock out and his fingers wrapped around his shaft, stroking himself to the image of the busty former idol. Mihoshi had been married and given birth, leaving much of the spotlight. These pictures were from when she was in her prime.

“Koichi, what are you doing?” asked Nanami.

“When you get bored at home, these things happen!” said Koichi. “It’s not like I was fapping to her because her proportions are similar to... yours...”

“To _mine_?” asked Nanami. “I didn’t know my brother was such a pervert. Just for that, I’m eating dinner with you. You need to talk to people more often. Mom and dad are starting to worry about you. I’m really sweaty from work and riding my bike here. Mind if I use your shower?”

Nanami stood outside the bathroom door. She took off her pants and her shirt, stripping down to just her underwear, sticky with sweat and showing the shape of her nipples through her bra. She unhooked her bra, letting her breasts fall down into their natural shape. She was young, so they were still quite perky, and her nipples were a shade of dark pink that stood out on her skin. Strands of pubic hair could be seen through the edges of her panties. She always wore pants when working in her garden, at the Gundam Base and on her bike, so she never shaved down there more than she needed to.

“Your hand’s still moving, but you’re not looking at your magazine anymore,” said Nanami. “Getting turned on from your little sister’s tits?” She squeezed her breasts together, making them look bigger. She approached Koichi, the smell of sweat coming off her body, and bent down to look at his dick. Her ass was raised in the air, showing off its fine curves.

“Nanami, don’t look down there!” said Koichi. He could feel her breath on his cock as Nanami inspected it.

“We used to bathe together as kids, but I don’t remember your dick being this big,” said Nanami. “You could please your girlfriend with this thing if someone taught you how to use it.”

“I’m fine staying here and masturbating,” said Koichi.

“You have to get out of the house at some point!” said Nanami. “If you won’t make an effort to get out and get laid, I’ll have to take your virginity for you.”

“What?” said Koichi.

Nanami pulled down Koichi’s pants and underwear, leaving him with nothing below the waist. She got a good look at his cock, hard from looking at Mihoshi’s nude gravure. He had peeled back his foreskin, and the length was a little above average for a man his age. Nanami was used to Koichi’s apartment - he kept it clean so he could work on his plastic models - but the stench of his cock was something she had never smelled before. It was manly and virile, with plenty of semen just waiting to be released from his balls.

“How many times a day have you been fapping?” asked Nanami.

“It’s only a few times a week...” said Koichi. “I spend more on plastic models than porno mags.”

“A few times a week is fine, but I’d rather you cum in your girlfriend than your hand,” said Nanami. “Watch. It’s much better when you let a woman handle your dick.”

She held Koichi’s balls in her hand, rolling them back and forth between her fingers. His scrotum was sticky with sweat and covered in hair. Nanami squeezed very lightly, warming up his semen within while she lowered her head. She kissed the tip of her brother’s dick before opening her mouth, taking his entire cockhead between her lips. Koichi was stunned, unable to say a word as his sister eagerly sucked on his cock with a delighted, coy expression.

The smell of Koichi traveled all the way into her nostrils. The manly scent spreading through her body was turning her own. A wet spot began to appear in Nanami’s sticky panties. She started sucking on his cock, bobbing her head up and down as she made loud sucking noises, hoping Koichi wouldn’t look away. Her suction was strong and her slurps were loud, her tongue digging into every sensitive spot on his cock until Koichi couldn’t hold back his moans anymore.

“This is much better than my hand... How many guys’ dicks have you sucked?” asked Koichi.

“You don’t need to know that,” said Nanami. “But I’ve practiced. Do you know how many guys I’ve turned down at work? They come in wanting to get a Gunpla and end up staring at my boobs. I care too much about you to let them get in the way of our bond.”

Just before the store was about to close, behind the shelves at the far back of the store, in the security camera’s blind spot, Nanami had let Riku and Yukki play with her boobs. She let the boys grope them and suck them, letting them know a woman’s body before she gave them a free blowjob with their Gundam purchase. She hadn’t let them penetrate her, but only because they were still growing.

Nanami took his dick out of her mouth, licking along the length of the shaft, letting some of her saliva drip onto his balls. Koichi was throbbing now, his head dribbling with precum. He was on the verge of a powerful orgasm, and he wanted to shoot it inside Nanami’s mouth. Nanami took her lips away, adjusting her position to wrap her breasts around the length of Koichi’s dick. The head emerged from her cleavage, still bright red and throbbing.

“Soft, aren’t they?” said Nanami. “When I take off my bra, my nipples get really hard. Look.” She brushed her hard tip against Koichi’s dick, drawing more precum out of his cock. “You love this. You don’t have to hold back. Cum whenever you want. All over your sister’s tits and mouth.”

She rubbed her breasts up and down, pushing her soft flesh against Koichi’s cock. She opened her mouth and let out a long line of saliva, dripping it into her cleavage to make her skin slicker. As she went faster, Koichi could no longer hold on. Nanami lowered her lips over Koichi’s dick, holding his glans in her mouth until he finally came. Hot ropes of cum splattered against her palate and her cheeks, filling her mouth with hot, salty jizz. Nanami let Koichi’s dick go from her mouth. She opened up, and let his load drop from her tongue onto her chest. It rolled down the curves of her bosom, covering her nipples in a white glaze.

“That must’ve felt good,” Nanami said. “And you’re still so hard. I can get you a job at The Gundam Base if you go all the way with me.”

Nanami stood up and slowly removed her panties. A line of sticky love juices trailed between her pussy lips and the front of her underwear. She was sopping wet, and her clit was poking out from its hood. Koichi could see the pink insides of her puffy pussy at this angle. She was thirsty for sex, and the only dick around was his own. Nanami ran her fingers through her brown bush, coyly spreading open her pussy to give Koichi a look.

“I don’t know about this...” said Koichi.

“You didn’t hesitate when I sucked you. You’re getting a rock-hard erection at the sight of your sister’s pussy. I know you want to do me. I don’t mind, it’ll be our little secret. Come on, you get naked, too,” said Nanami playfully.

She removed Koichi’s shirt, revealing his abs. He was in pretty good shape for someone who had been living inside his apartment for years, with the exception of getting food. Nanami pushed Koichi onto his back on the carpet, holding his legs up and spreading them apart. She approached, her pussy dripping down her thighs. This raw, throbbing cock looked so much better than any of her toys.

Koichi’s cockhead rubbed against his sister’s dripping pussy. Nanami, her legs spread and holding onto Koichi’s ankles, straddled him. His hard cock pushed aside her lips, sliding into her wet slit with ease. Nanami let out a happy moan as her brother’s dick made its way inside her warm folds. She squeezed down, keeping Koichi’s cock locked in her like a vise grip.

“Our bodies are really compatible,” said Nanami. “I’m going to start moving.”

“Nanami, stop! Siblings shouldn’t do this kind of thing!” said Koichi.

Nanami didn’t listen. She bounced her springy ass on his dick, letting Koichi get a good look at the point where they connected. She pulled out far, letting her juices drip down the length of his hard shaft, before sliding back in with a squishing noise. She found a steady rhythm to her fucking, keeping Koichi at the mercy of her pussy. Nanami started to sweat again as she rode her brother’s dick, her pussy tingling with pleasure.

“No, Koichi! A shut-in who can’t sexually satisfy a woman shouldn’t rejoin society!” said Nanami. “This is important for you.”

The two of them were moaning, keeping it low enough that the people living below and next door to Koichi wouldn’t hear. He didn’t want to admit it, but he had never had sex with a woman before. If he kept this up any longer, he might become a wizard. Thanks to Nanami’s help and her tight, hot pussy, that wasn’t going to happen. The way it squeezed his dick in just the right parts, keeping it hard but not letting him cum, was dragging him into a state of lucid pleasure, unable to think of anything else but satisfying his libido.

He glanced at Nanami’s ample chest. With each successive thrust, her breasts swung up and down, slapping against her torso and sending drops of sweat flying off her body. His eyes followed her nipples, those hard pink tips starting to blur as Nanami’s speed grew faster. She wanted to keep having sex with Koichi until his balls were completely drained. Then he might have the clarity of mind to think about getting a job and helping his sister out.

“I have to pull out!” said Koichi.

“No, you won’t! You’re cumming inside me or nothing!” said Nanami. She gave him a knowing wink. “It’s a safe day.”

Those words ignited Koichi’s lust in a whole new way. He thought of the many outfits at The Gundam Base, and knew that Nanami loved to cosplay in them. He wanted to see Nanami dressed as Rain from _G Gundam_ , pulling aside that pink skirt and pounding this pussy again. Nanami would be up for it, too. She was riding him like her motorcycle, humping along until she stopped. Koichi extended his hands and grabbed onto her breasts, pressing his fingers down into her soft tits.

“Koichi?” Nanami asked. “You’re finally taking the lead.”

“Thank you, Nanami!” he said. “Your body is so sexy!”

Koichi massaged her breasts, getting a feel for their weight and softness. Nanami had plenty of chest to grab onto, and though they had ceased bouncing, her brother’s hands made her go even faster and harder on his dick. Those same hands that had carefully put together the Gunpla from the shop were now teasing her breasts, his fingertips getting closer to her hard nipples. Koichi moved his thumb and forefinger around her pink tips, rubbing them. Nanami tried to hold in her moans, the pleasure spreading downward from her nipples all the way to her clit.

Inside her pussy, she clenched even tighter around Koichi’s dick. His balls were brushing against her thighs, and her pussy juices were spilling out. The two of them could barely hold on much longer. They let out a loud moan at the same time. Koichi pushed his dick as far into her pussy as he could go, and splurted everything from his balls inside Nanami’s pussy. It overflowed back down onto his cock. He stayed inside Nanami until he had gone limp, the two of them hugging in a sweaty, sticky embrace. Their bodies were flushed bright red as they basked in the afterglow of sex.

“Let’s take a shower and eat,” Nanami said.

“Sure,” said Koichi, his glasses fogged up.

They showered off together. They soaped up each others’ bodies, the small space letting them stay close to each other. Nanami felt Koichi’s dick brush against her body, and teased it with her hands until it was rock solid. Nanami had only brought one set of clothes, and used Koichi’s washer and dryer. She was naked while she ate dinner with her brother, the two of them talking about old times. Nanami let him know what was going on in Gundam Battle Nexus Online, and told him that the Build Divers needed his assistance.

“I’ve been thinking about playing the game myself some day,” said Nanami. “Riku, Yukki and Momo always look like they’re having fun.”

“I’m not onboard with this VRMMO thing, but I’ll give it all I’ve got,” said Koichi. “If you have a few spare minutes during work...”

“I’m not gonna forget a dick like that after it was inside me,” said Nanami. “Meet me on the roof. We can have some fun in my private garden.”

When people visit The Gundam Base, the two employees, brother and sister, get along very well. When the store is closed for the night, they get along better than one would expect. Nanami kept her promise to Koichi to help him rejoin society, and the two of them found themselves in a world of endless pleasure.


End file.
